Financial Instruments (Tables)

6 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Schedule of carrying amount and estimated fair values of our exchangeable notes as well as current and long-term debt

The following table presents carrying amounts and estimated fair values of current and long-term debt and financing obligations:

	Carrying amount at September 30, 2017		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt and financing obligations	$	38,174	$	32,908	$	3,029	$	5,584	$	41,521

	Carrying amount at March 31, 2017		Estimated Fair Value Using Input Type
			Quoted prices in active markets		Observable		Unobservable		Total estimated fair value
	(in millions)
Current and long-term debt and financing obligations	$	40,581	$	33,196	$	4,352	$	5,468	$	43,016